SYNTHESIS AND CHARACTERIZATION OF SUBSTITUTED (1,2-NAPHTHALOCYANINATO)IRON COMPOUNDS AND BISAXIALLY COORDINATED ISOCYANIDE COMPLEXES

Tetrasubstituted (1,2-naphthalocyaninato)iron(II) compounds t-Bu4-1,2-NcFe (13), Me4-1,2-NcFe (14), and Ph4-1,2-NcFe (15) are obtained from 7-substituted 1,2-dicyanonaphthalenes 12a-c either by reaction with pentacarbonyliron in 1-chloronapthalene (method a) or with iron(II) acetate in 1-hexanol (method b), respectively. Compounds 13-15 were characterized by UV/vis, IR, and Mossbauer spectroscopy, and the oxidation potentials, measured by cyclic voltammetry in pyridine, are compared with the oxidation potentials of 1,2-NcFe and PcFe. The substituted (1,2-naphthalocyaninato)iron compounds 13, 14, and 15 react with alkyl and aryl isocyanides R'NC (R' = t-Bu, c-Hx, Bz, Me2Ph), yielding the bisaxially coordinated isocyanide complexes of 13, 14, and 15, R4-1,2-NcFe (R'NC)2. Due to their comparatively high solubility in organic solvents, it is possible to characterize the isocyanide complexes with H-1 and C-13 NMR spectroscopy. The H-1 NMR spectra of, for example, t-Bu4-1,2-NcFe(t-BuNC)2 reveal that only one of the structural isomers of the unsymmetrical 1,2-naphthalocyanine macrocycle, namely, the 1,2-naphthalocyanine with C4h symmetry (see Figure 1) is formed, if the synthesis starting with 7-tert-butyl-1,2-dicyanonaphthalene (12a) is carried out according to method a. The crystal structure of the isomer obtained, t-Bu4-1,2-Nc(t-BuNC)2, is determined (Figure 4) and confirms these findings. All isocyanide complexes R4-1,2-NcFe(R'NC)2 are characterized by spectral data and thermoanalyses. The reaction of R4-1,2-NcFe 13, 14, and 15 with diisocyanobenzene (dib) leads to the bridged compounds [R4-1,2-NcFe(dib)]n, R = t-Bu, Me, Ph. After being doped with iodine, the bridged complexes exhibit good semiconducting properties.